Autonomous vehicle localization system

ABSTRACT

Autonomous vehicles may communicate with each other to avoid hazards, mitigate collisions, and facilitate the flow of traffic. To enhance such cooperation, it would be highly advantageous if each vehicle were able to determine which vehicle in view corresponds to each communication message, which is generally unknown if a plurality of vehicles are in range. Systems and methods provided herein can enable autonomous vehicles to determine the spatial location of each proximate vehicle by detecting a pulsed localization signal emitted by each of the other vehicles. In addition, each vehicle can transmit a self-identifying code, synchronous with the emitted localization signal, so that other vehicles can associate the proper code with each vehicle. After such localization and identification, the vehicles can then cooperate more effectively in mitigating potential collisions.

PRIORITY CLAIMS AND RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/782,672 titled “Infrared Pulse for Autonomous Vehicle Identification”filed Dec. 20, 2018, and U.S. Provisional Application No. 62/832,499titled “Autonomous Vehicle Localization System” filed Apr. 11, 2019,which are hereby incorporated by reference in entirety. This applicationis also related to U.S. Pat. No. 9,896,096, issued Feb. 20, 2018entitled “SYSTEMS AND METHODS FOR HAZARD MITIGATION” and U.S. patentapplication Ser. No. 16/148,390, filed Oct. 1, 2018 entitled “Blind SpotPotential-Hazard Avoidance System” the contents of which areincorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The invention relates to systems and methods for short range locatingand identification of positions of vehicles.

BACKGROUND OF THE INVENTION

Autonomously operated vehicles are expected to facilitate the flow oftraffic and reduce traffic accidents by cooperating with otherautonomous vehicles. Such cooperation requires communication between thevehicles. However, intervehicle cooperation is greatly hampered sinceautonomous vehicles generally cannot determine which of the vehicles intraffic corresponds to each wireless communication. Although autonomousvehicles generally have all-around cameras to image other vehicles, andwireless transceivers for wireless communication with other vehicles,they are unable to associate each message with any particular vehicle.Without knowing which vehicle is transmitting a message, cooperation ishighly limited.

Wireless messages may include an identifying code such as the licenseplate code of the transmitting vehicle, but often the license plate isnot visible due to intervening traffic, or may be missing in front, andfor many other reasons cannot serve to localize the transmitting vehiclespatially. Vehicles can transmit their GPS coordinates, but these aregenerally not accurate enough to localize closely-spaced vehicles, andin many cases GPS is not available or is too slow to indicate whichphysical vehicle is associated with each wireless message. Sinceautonomous vehicles lack means for correlating the messages with thevehicles that transmitted them, full cooperation is not feasible.

What is needed is means for determining which autonomous vehicle, amonga plurality of vehicles in traffic, is associated with each wirelessmessage. Such a system and method would enable cooperation amongautonomous vehicles, thereby enhancing the flow of traffic, avoidingcollisions, minimizing the harm of any unavoidable collisions, andsaving lives.

This Background is provided to introduce a brief context for the Summaryand Detailed Description that follow. This Background is not intended tobe an aid in determining the scope of the claimed subject matter nor beviewed as limiting the claimed subject matter to implementations thatsolve any or all of the disadvantages or problems presented above.

SUMMARY OF THE INVENTION

A system, mounted on a first vehicle, for localizing a second vehicle,comprises a wireless transmitter configured to transmit a first wirelessmessage; a localization signal emitter configured to emit a firstlocalization signal comprising pulsed energy synchronized with the firstwireless message; a wireless receiver configured to receive a secondwireless message from the second vehicle; a localization signal detectorconfigured to detect a second localization signal from the secondvehicle, the second localization signal comprising pulsed energysynchronized with the second wireless message; and a processorconfigured to cause the localization signal emitter to emit the firstlocalization signal synchronously with the first wireless message, todetermine a direction of the second vehicle according to the secondlocalization signal, and to associate the second localization signalwith the second wireless message.

This Summary is provided to introduce a selection of concepts in asimplified form. The concepts are further described in the DetailedDescription section. Elements or steps other than those described inthis Summary are possible, and no element or step is necessarilyrequired. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended foruse as an aid in determining the scope of the claimed subject matter.The claimed subject matter is not limited to implementations that solveany or all disadvantages noted in any part of this disclosure.

These and other embodiments are described in further detail withreference to the figures and accompanying detailed description asprovided below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sketch of an exemplary autonomous vehicle denotingvarious subsystems.

FIG. 2 is a sketch showing two vehicles configured with exemplarylocalization systems.

FIG. 3A is a sketch showing two vehicles configured with anotherexemplary localization system.

FIG. 3B is a schematic showing exemplary pulses comprising an autonomousvehicle identification and localization signal.

FIG. 4A is a schematic showing an exemplary sequence of wirelessmessages and localization pulses versus time.

FIG. 4B is a schematic showing another exemplary sequence of wirelessmessages and localization pulses versus time.

FIG. 4C is a schematic showing another exemplary sequence of wirelessmessages and localization pulses versus time.

FIG. 5 is a sketch in perspective showing an exemplary localizationsystem.

FIG. 6 is a sketch in perspective showing another exemplary localizationsystem.

FIG. 7 is a sketch in perspective showing a different exemplarylocalization system.

FIG. 8 is a sketch in perspective showing an exemplary simplifiedlocalization system.

FIG. 9 is a top-view cross-section sketch showing the distribution oflocalization signal detectors arranged around a circular enclosure.

FIG. 10 is a notional schematic of a circuit for detecting pulse-codedlocalization signals.

FIG. 11 is a sketch showing several vehicles in which one is emitting anexemplary localization pulse.

FIG. 12 is a sketch showing several vehicles in which one is emitting anexemplary visible-light localization pulse.

FIG. 13 is a sketch showing sequential positions of three cars in atraffic lane at successive times in which a collision occurs.

FIG. 14 is a sketch showing sequential positions of three cars in atraffic lane at successive times, in which a collision is avoided.

FIG. 15 is a flowchart showing an exemplary method for two vehicles toexchange messages synchronized with localization pulses.

FIG. 16 is a flowchart showing an exemplary method for two vehicles tospatially localize each other.

FIG. 17 is a flowchart showing an alternative exemplary method for twovehicles to spatially localize each other.

FIG. 18 is a flowchart showing another alternative exemplary method fortwo vehicles to spatially localize each other.

FIG. 19 is a schematic sketch showing time traces such as oscilloscopetraces for various steps of an exemplary localization process.

FIG. 20 is a schematic sketch showing time traces such as oscilloscopetraces for various steps of another exemplary localization process.

FIG. 21 is a flowchart showing an exemplary method whereby two vehiclescan cooperate to avoid a collision.

FIG. 22 is a flowchart showing an alternative exemplary method wherebytwo vehicles can cooperate to avoid a collision.

DETAILED DESCRIPTION

Systems and methods are disclosed that enable autonomously-operatedcomputer-driven vehicles (“autonomous vehicles”) to identify andlocalize other autonomous vehicles in traffic. The disclosed“localization” systems and methods may enable autonomous vehicles todetermine which particular vehicle, among other proximate vehicles, istransmitting a particular wireless message. Knowledge of which physicalvehicle is associated with each wireless message can greatly enhance theability of the autonomous vehicles to cooperate with each other inavoiding collisions. Additionally, the systems and methods may enableautonomous vehicles to associate a respective identification code witheach of the other vehicles in view. With knowledge of which vehicle isassociated with which code, the autonomous vehicles can then communicatemore easily and cooperate more effectively in avoiding collisions andregulating the flow of traffic.

The localization systems and methods may include a localization signalcomprising pulsed energy which may be emitted by each of the vehicles.The direction of the localization signal may then be determined by theother vehicles, thereby determining the direction of the emittingvehicle. When compared to an image (such as a camera image) thatincludes the emitting vehicle, the localization signal may therebydetermine which particular vehicle, among a plurality of vehicles inview, emitted the localization signal. The localization signal thus mayserve as a semaphore indicating which particular vehicle is emitting thelocalization signal at any particular time. In addition, thelocalization signal may be coupled with a wireless message, therebyestablishing which vehicle is transmitting that particular wirelessmessage; namely, whichever vehicle is also emitting the localizationsignal associated with the wireless message. For example, the wirelessmessage and the localization signal may be synchronous or simultaneousor otherwise correlated in time. For example, the wireless message andthe localization signal may at least partially overlap in time, or thewireless message may occur first with the localization signal beginningas the wireless message ends, or the localization signal may start firstand the wireless message may begin as the localization signal ends, orother temporal relationship between the wireless message and thelocalization signal. Moreover, the localization signal may be emittedsynchronously with, or responsive to, a particular icon in the wirelessmessage, such as a word or code or bit pattern or other feature of thewireless message. As used herein, “synchronous” means having a temporalrelationship, so that the wireless message and the localization signalare synchronous when they have a temporal relationship with each other.

Each vehicle may have an identification code associated with thatvehicle. Preferably each identification code is unique or otherwiseprotected against duplication among traffic vehicles. The wirelessmessage may contain the identification code of the transmitting vehicle,in which case the other vehicles can receive both the localizationsignal and the wireless message, and thereby associate theidentification code with the particular physical vehicle thatsynchronously emitted the localization signal. By determining theidentification code of each vehicle, the vehicles can subsequentlycommunicate with each other using wireless messages and thereby identifythe transmitting vehicle, and optionally the intended recipient as well.For example, the wireless message can mention the identification code ofthe transmitting vehicle to indicate which vehicle is the source of themessage, and may also mention the identification code of a particularrecipient vehicle for which the message is intended. In addition, eachvehicle may store the identification code of each vehicle in view and,by tracking the other vehicles as they move, may be able to sendmessages to particular vehicles using the stored identification codevalues. Thus it may not be necessary to repeat the localization signalupon each wireless message, since the vehicle identification code isincluded in the wireless message, so long as the identification codeshave already been determined by the proximate vehicles.

To consider a particular example, a first vehicle may transmit awireless message that includes the first vehicle's identification code,and may simultaneously emit a localization signal such as a light pulse.A second vehicle can detect the localization signal using, for example,a camera or a directional detector, and can thereby determine adirection toward the first vehicle relative to the second vehicle. Thesecond vehicle can then compare the direction of the emitting vehicle toan image or other spatial distribution that includes vehicles near or inview of the second vehicle, thereby determining which of those vehiclesis the first vehicle. The second vehicle thereby determines whichparticular vehicle is associated with the concurrent wireless message.Determining which vehicle is associated with which identification codegreatly enhances cooperation between the vehicles thus localized. Eachof the other vehicles in range can then transmit wireless messagessynchronously with localization signals, which the other vehicles candetect and thereby localize each other vehicle. The localizationprocesses may continue until each of the vehicles within range, orwithin view, or proximate to the first vehicle, have been localized bythe other vehicles.

In a first embodiment (Mode-1), each vehicle emits a localization signalupon each wireless message. Other vehicles can determine which vehicleis transmitting each message by detecting the concurrent localizationsignal. In a second embodiment (Mode-2), each vehicle emits an initiallocalization signal while synchronously transmitting a wireless messagethat contains the transmitting vehicle's identification code. Othervehicles can receive the wireless message and the localization signal,record the vehicle identification code from the wireless message, anddetermine which particular vehicle is associated with thatidentification code by detecting the localization signal. Each vehiclemay communicate wirelessly thereafter, by including their vehicleidentification code in each wireless message, without having to repeatthe localization process each time. In a third embodiment (Mode-3), eachvehicle emits a localization signal that is modulated to encode theemitting vehicle's identification code, with or without a concurrentwireless message. Other vehicles detecting and decoding the encodedlocalization signal can thereby determine which identification codebelongs to the emitting vehicle. Thereafter, the vehicles cancommunicate wirelessly by including their identification code in eachwireless message, without having to repeat the localization signal.

The localization system may include means for transmitting and receivingwireless messages, and means for emitting and detecting pulsedlocalization signals that indicate the location of the emitting vehicle,and means for determining the direction of each localization signal, andmeans for comparing the direction of the localization signal to thedirections of vehicles in view, thereby determining which vehicle is theemitting vehicle. The system may include a processor configured tocontrol the wireless transmission and reception processes, thelocalization signal emission and detection processes, and the imaging,direction, and localization determination processes. Each vehicle inrange that has a compatible localization system may participate in thelocalization procedure with each of the other vehicles, thereby enablingcommunication among them with knowledge of which physical vehicle istransmitting or receiving each message, and thereby enhancingcooperation among the participating vehicles.

While the examples provided herein are primarily directed towardautonomous vehicles, the same systems and methods are applicable toother vehicles that include automatic means for influencing theoperation of the vehicle. The systems and methods are applicable tohuman-driven vehicles equipped with the localization system andsemi-autonomous driving assistance systems such as an automatic brakingsystem to avoid front-end collisions, an automatic speed control systemto maintain intervehicle distances, an automatic lane-keeping assistant,and the like. The systems and methods are also applicable to vehiclestemporarily controlled by processors during, for example, an emergencyintervention procedure, and to many other types of vehicles havingsuitable means for emitting and detecting the localization signals. Inaddition, the systems and methods may be applicable to vehicles that areentirely human-driven that lack any means for automatically influencingthe operation of the vehicle, but which include means for communicatingwith the driver by, for example, a radio message, focused acousticalenergy, etc. In one embodiment, a human-driven vehicle may include anemergency intervention system as well as a localization system accordingto the present disclosure. A collision may be imminent, but theemergency intervention system may not yet be aware of the hazard. Inthat case, another vehicle (such as the vehicle that is about to collidewith it) may send an urgent wireless message to the human-drivenvehicle, thereby prompting the emergency intervention system toimmediately assume control and take action to avoid the collision.

A vehicle is “autonomous” if it is operated primarily or solely by aprocessor. An autonomous vehicle may be operated with little or noparticipation by a human, other than to specify the destination.Alternatively, the autonomous vehicle may be operated by a processoronly temporarily, such as an emergency intervention system that takescontrol of the vehicle only long enough to avoid a collision, and thenreturns control back to a human driver. In some embodiments, a vehiclemay be semi-autonomous with automatic braking, lane-keeping, speedcontrol, potential-hazard avoidance, and/or blind-spot avoidancesystems. In the examples, a “first vehicle” is a particular vehicle inwhich the localization system is installed. The “second vehicle” isanother vehicle proximate to the first vehicle. The second vehicle is“proximate” to the first vehicle if they are close enough to cooperatein avoiding collision. The second vehicle is “within range” of the firstvehicle if they can exchange wireless messages. The second vehicle is“in view” of the first vehicle if the sensors (or driver) of the firstvehicle can detect visible-light or infrared signals emitted by thesecond vehicle. The “localization procedure” is a method or process oftransmitting wireless messages and associated localization signals toother vehicles, and of receiving wireless messages and localizationsignals of other vehicles, and determining which vehicle has transmittedeach wireless message. “Localizing” a vehicle means determining whichparticular vehicle, among a plurality of vehicles in view, has emitted alocalization signal. Both of the first and second vehicles, and anyother vehicles in range, may have a localization system installed andmay determine which vehicle is associated with which wireless message.Each vehicle may include an autonomous vehicle controller, such as aprocessor configured to plan and implement the driving. The autonomousvehicle controller, or other processor, may also be configured to detectan imminent collision, and to cooperate with other autonomous vehiclesin avoiding or mitigating the collision. Often in fast-paced freewayconditions, an imminent collision cannot be avoided by vehicles actingon their own, but can be avoided by the cooperative actions of multiplevehicles. Often such cooperation depends on knowing the location andidentification of each of the other vehicles. For example, the processormay be configured to select a first sequence of actions for the firstvehicle to implement and a second sequence of actions for the secondvehicle to implement, so that together they can avoid a trafficcollision. Non-emergency traffic flow can also be greatly improved withsuch vehicle-to-vehicle communication. However, such cooperation dependson each vehicle having determined where each other vehicle is located.If the first vehicle cannot associate each wireless message with aparticular vehicle, then cooperation is hindered. The localizationsystems and methods according to the present disclosure may provide anassociation between each vehicle's location and its wireless messages.

The vehicle in front of the first vehicle is the “leading vehicle”, andthe vehicle behind the first vehicle is the “following vehicle”. Avehicle encroaching upon the first vehicle from the side is the“encroaching vehicle”. Any vehicle in the lane on the opposite side ofthe first vehicle from the encroaching vehicle is the “oppositevehicle”. A vehicle in the lane to the right of the first vehicle is the“right-side” vehicle, and similarly for the left lane. The drivers orautonomous vehicle controllers of the respective vehicles are referredto in the same way, and each lane is referred to in the same way. Eachvehicle may be an automobile, a truck, a bus, a motorcycle, or any othermotorized conveyance that may travel on a road or highway. Each vehiclemay be autonomously driven or human-driven or temporarily controlled byan automatic emergency intervention system for example.

As is well known in physics, the terms “acceleration” and “accelerating”include any change in velocity, including positive, negative, andlateral changes. Although in common usage, people often treat“acceleration” as speeding up, the technically proper meaning includesall velocity changes in any possible direction. Therefore,“acceleration” as used herein includes “positive acceleration” orspeeding up in which the forward speed of the subject vehicle isincreased, “passive deceleration” in which the forward speed of thesubject vehicle is reduced by reducing the engine power, “activedeceleration” or “braking” by applying the brakes, and “lateralacceleration” or “steering” in which the direction of the subjectvehicle's motion is changed. In practice, positive acceleration iscaused by depressing the accelerator pedal, negative acceleration ordeceleration is caused by depressing the brake pedal or releasing theaccelerator pedal, and lateral acceleration or steering is caused byturning the steering wheel. Thus, the general term “acceleration”includes speeding up, slowing down, and changing the direction of thesubject vehicle's motion.

A “strategy” is a plan comprising a sequence of actions in a particularorder, configured to accomplish a specific purpose, for example to avoida collision or to minimize its harm. A “sequence” or “sequence ofactions” or “set of sequential actions” comprises one or more actions,such as acceleration or deceleration or steering actions or waitingperiods, in a particular order. The sequence may further include aspecification of the magnitude of each action in the sequence, as wellas its duration and timing. The actions may overlap in time, such asbraking and steering at the same time. The actions may further includeany other item, behavior, or effect that the processor can initiate,such as illuminating the brake lights, sounding the horn, sending amessage, activating a dashboard indicator, adjusting a sensor,performing a calculation, reporting a result, setting a parameter, andso forth. The sequence of actions may include thresholds (such as“accelerate until matching the leading vehicle”) and/or contingencies(such as “illuminate brake lights if the leading vehicle slows down”).The sequence may include branches (such as “if the following vehiclecontinues to accelerate, switch to the harm-minimization strategy”). Thesequence of actions may be implemented by a processor sending controlsignals to control the vehicle throttle, brakes, and steering, andoptionally the lights and other controls. Preferably, the controlsignals are adjusted by feedback, in which sensors measure the position,velocity, or acceleration of the vehicle, and any deviation from theexpected trajectory would cause the processor to revise the controlsignals in a way to bring the vehicle motion into agreement with thepredetermined sequence of actions. “Direct mitigation” comprisescontrolling the throttle, brakes, and steering of the vehicle accordingto the selected sequence, with or without feedback from the internalsensor data. “Indirect mitigation” comprises controlling anything else,such as turning off the fuel pump, rolling down the windows, flashingthe brake lights, sounding the horn, alerting the driver or occupants,sending a help-request message, and the like.

The “harm” of a collision includes negative consequences of thecollision, preferably quantified according to a valuation scheme. Such ascheme may place high value on saving lives, a lower but still highvalue on preventing injuries, and also a value on any physical damagecaused by the collision. Then the overall harm of the expected collisionmay be quantified by multiplying each type of harm times its valuation,and then adding together all the types of harms expected for thecollision. The various types of harm may also be multiplied byprobability factors to account for uncertainties. Thus, a harmcalculation related to an imminent high-speed collision may include anentry for possible loss of lives, whereas a low-speed collision mayinclude mainly property damage costs. As used herein, the “minimum-harmsequence” is a particular sequence of actions that is expected toproduce less harm than the other sequences so far analyzed.

Turning now to the figures, FIG. 1 is a schematic of an exemplaryautonomous vehicle including sensors, processors, communicationssystems, and electromechanical systems. The sensors may include internalsensors configured to measure the speed, acceleration, and/or bearing ofthe vehicle, the state of the engine, and/or the state of anyhuman-operated controls such as the steering wheel, accelerator pedal,and brake pedal, among other controls. The sensors may also includeexternal sensors configured to measure data about other vehicles such aslidar, radar, sonic, and/or Doppler systems to measure distances and/orspeeds of other vehicles, cameras in visible and/or infrared light, andany other sensors on the vehicle.

The processors may include one or more physical processing modules,configured to autonomously operate the first vehicle. The processors maybe configured to drive the vehicle in normal traffic and/or in emergencyconditions. The processors may include a processor configured to planand implement a driving route autonomously, according to a destinationand route preferences that are specified by a human occupant. Theprocessors may include a processor configured to detect other vehicles,a processor configured to project traffic motions forward in time andthereby to detect an imminent collision, and a processor configured todevise and calculate sequences of actions such as accelerations,decelerations, and steering of the vehicle. The processors may furtherinclude a processor configured to determine whether an imminentcollision is avoidable if the vehicle were driven according to each ofthe sequences, and/or if the other vehicle or vehicles were drivenaccording to various sequences. The processor may be further configuredto determine that the collision is unavoidable if none of the sequencescan avoid the collision. A processor may be configured to calculate theharm of a collision according to the projected collision parameters suchas the relative velocity of the colliding vehicles, the strike points onboth vehicles, and other data affecting the collision. A processor maybe configured to calculate the harm according to a formula that mayinclude the number of expected fatalities, injuries, and/or propertydamage, optionally weighted by suitable coefficients and/or probabilityfunctions. When the collision is avoidable, a processor may beconfigured to select a particular avoidance sequence which is a sequenceof actions that is calculated to avoid the collision. When the collisionis unavoidable, a processor may be configured to select a least-harmsequence which is a sequence of actions that is calculated to result inthe least harm. A processor may be configured to implement the selectedsequence of actions by transmitting suitable signals to the acceleratoror throttle, brakes, and/or steering of the vehicle according to theselected sequence.

The processors may comprise a computing environment optionallyassociated with non-transitory computer-readable media. The computingenvironment may include a computer, CPU, GPU, microprocessor,microcontroller, digital signal processor, ASIC, or other digitalelectronic device capable of analyzing data from sensors and preparing acollision-avoidance or a harm-minimization sequence of actions, whichmay include controlling the acceleration or deceleration or steering ofthe subject vehicle according to the sequence of actions. The computingenvironment may include one or more processors, each processor beingconfigured to perform one or more of the computing tasks, including suchtasks as autonomously driving the subject vehicle, analyzing sensordata, calculating future positions of vehicles, calculating the harmassociated with a possible collision, determining whether an imminentcollision is avoidable or unavoidable, selecting a sequence of actionsto implement, and implementing the sequence of actions by transmittingcontrol signals to the accelerator, brakes, steering, etc. Thenon-transitory computer-readable media comprise any digital data storagemedia capable of storing instructions such as software instructionsthat, when executed, cause the computing environment to perform a methodfor mitigating vehicle collisions, including avoiding a collision whenpossible and minimizing the harm of a collision when unavoidable.Examples of such media include rotating media such as disk drives andCD's, solid-state drives, permanently configured ROM, detachablememories such as removable drives and micro-SD memories, and the like,in contrast to transitory media such as a computer's working memory(RAM, DRAM, cache RAM, buffers, and the like).

The processors may include a processor configured to analyze wirelessmessages, and/or a processor configured to analyze localization signalsfrom other vehicles. A processor may be configured to determine whichvehicle, among a plurality of vehicles proximate to the first vehicle,transmitted the wireless message. A processor may be configured toextract and record a vehicle identification code contained in thewireless message or in the localization signal. A processor may beconfigured to analyze a camera image or other directional detector data.A processor may detect vehicles proximate to the first vehicle in theimage or the detector data. A processor may detect a localization signalin the image or the detector data, and to spatially correlate thelocalization signal with a particular one of the other vehiclesproximate to the first vehicle, thereby determining which of the othervehicles emitted the localization signal. The image or directional datamay include both the localization signal and the proximate vehicles;alternatively, the vehicles may be imaged separately from thelocalization signal and subsequently correlated by, for example, imageanalysis. A processor may be configured to track or follow the positionor direction of another vehicle using, for example, image processing orother suitable time-sequential measurement means. A processor may beconfigured to associate wireless messages that include a particularvehicle identification code with a particular vehicle that waspreviously localized using an earlier localization signal.

The communications module may include wireless means for V2V(vehicle-to-vehicle) communication between autonomous vehicles, V2A(vehicle-to-anyone) communications with non-vehicle receivers such asfirst responders for example. The communication module may furtherinclude receivers such as GPS and internet receivers for weather and mapdata, and the like. The communications module may include a wirelesstransmitter and a wireless receiver such as a radio-frequencytransceiver. The communications module may further include opticalcommunication means such as a light pulse or infrared pulse emitter,configured to emit a vehicle localization signal, such as a visible orinfrared light pulse or series of such pulses. The communications modulemay further include a localization signal detector configured to detectlocalization signals such as visible or infrared pulses. Thelocalization signal detector may be an imaging-type detector, or adirectional detector, or otherwise configured to determine the directionof a localization signal. The communications module may include meansfor operating the horn, brake lights, and other lights aboard thevehicle.

Means for wireless communication may include radio-frequencytransmitters and receivers. Optical imaging means may include still orvideo cameras sensitive to infrared and/or visible light. The opticalimaging means may be sensitive to the localization signal, and maythereby determine the direction of the emitting vehicle by detecting thedirection of the localization signal. Alternatively, the optical imagingmeans may be sensitive to vehicles but insensitive to the localizationsignals, in which case a separate localization signal detector may beincluded. If so, such a localization signal detector may be adirectional detector configured to determine the direction of anarriving localization signal. Means for emitting localization signalsmay include light-emitting diodes (LEDs) or other types of lamps,configured to emit one or more pulses, in the infrared or visible orother light bands.

The localization signal may comprise pulsed energy. For example, thelocalization signal may include one or more electromagnetic energypulses, such as an infrared or visible light pulse or a series of suchpulses. The localization signal detector may be an imaging type sensorsuch as a camera or a plurality of cameras, or a non-imaging directionaldetector or a plurality of such detectors, or other suitable detectorconfigured to determine the direction of the localization signal. Thelocalization signal detector may be configured to image the secondvehicle concurrently with the localization signal on the same image,such as an image that records both visible and infrared light, therebydetermining directly from the image which vehicle is the emittingvehicle. Alternatively, the localization signal detector may beconfigured to measure the direction of the localization signal, while aseparate imager is configured to image the second vehicle, in which casethe processor may be configured to correlate the measured direction ofthe localization signal with the particular vehicle in the image that isin the same direction as the localization signal, and thereby determinewhich vehicle is associated with which identification code.

The vehicle identification code is a code or data suitable foridentifying each vehicle among other vehicles in traffic. The vehicleidentification code may be the license plate code, the VIN number, arandom alphanumeric string, or other vehicle-identifying code.Preferably each vehicle has a unique identification code, or at leasteach code is sufficiently detailed that two vehicles with the sameidentification code would be unlikely to be in range of each other. Insome embodiments, a particular vehicle may be configured to determinewhen another vehicle has the same identification code as the particularvehicle, and responsively may change its identification code permanentlyby, for example, adding a randomly selected number or letter to the endof its code. In this way, each vehicle can detect when another vehicleasserts the same identification code in a wireless message and can thenrevise its own identification code, thereby providing that each vehiclecan continue to have different codes thereafter. Each vehicle maytransmit its identification code in a wireless message. Each vehicle mayemit a localization signal that includes the identification code encodedin, for example, a sequence of pulses. Each vehicle may transmit awireless message and a localization signal concurrently, orsynchronously, or otherwise in a way that associates the wirelessmessage with the localization signal. For example, the localizationsignal may be emitted during the wireless message, such as continuouslyor periodically during the wireless message, or the localization signalmay be emitted upon a particular word such as “now” or other indicatorwithin the wireless message, or at the beginning or the end of thewireless message. Other vehicles may receive the localization signal andthe identification code concurrently, and may thereby associate thewireless message with the emitting vehicle. In addition, vehicles thatdetect the localization signal and the associated vehicle identificationcode may record that association in, for example, computer memory, orthe like. After localizing a second vehicle, a first vehicle can thentrack the location of the second vehicle using, for example, cameras. Inaddition, the first vehicle can send a wireless communicationspecifically to the second vehicle by referring to the second vehicle'sidentification code in the wireless message, including an indicationthat the message is intended for the second vehicle. The first vehiclecan also indicate that the wireless message is from the first vehicle byincluding the first vehicle's identification code in the wirelessmessage, along with an indication that the message is from the firstvehicle. The first vehicle can direct a wireless message specifically tothe second vehicle and also show that the message is from the firstvehicle by including the first vehicle's identification code in themessage with an indication that the first vehicle is the transmittingvehicle, and by including the second vehicle's identification code inthe message with an indication that the second vehicle is the intendedrecipient of the message. With such specificity in communication, thevehicles can cooperate with each other to facilitate the flow oftraffic, avoid potential hazards, avoid collisions, and/or minimize theharm of unavoidable collisions.

The electromechanical module may include means for driving andcontrolling the vehicle. For example, the driving and controlling meansmay include electrical, mechanical, hydraulic, and/or other types oflinkages configured to adjust the accelerator or throttle of thevehicle, linkages to apply the brakes including controlling the brakepressure and optionally controlling the brakes of each wheel separately,and linkages to control the steering. The electromechanical module mayfurther include means for releasing the door locks, rolling down thewindows to permit escape, turning off the engine and fuel pump, turningon the interior lights, and other items to assist the occupants in anemergency. The electromechanical module may further include indicatorsand alarms and the like to inform the occupants of any problems.

FIG. 2 shows schematically two vehicles performing an exemplarylocalization procedure. The first vehicle 201 includes a wirelesstransmitter 205 transmitting a wireless message 206. The wirelessmessage 206 in this case is a “hailing” message, which is a wirelessmessage that invites other vehicles to perform a localization procedure.The hailing message, and preferably each wireless message from eachvehicle, may include the identification code of the transmittingvehicle. The second vehicle 202 includes a wireless receiver 207configured to receive the hailing message 206 and other wirelessmessages. The first vehicle 201 is further equipped with a localizationsignal emitter 203, which emits a localization signal 204 such as aninfrared flash. Typically, the localization signal 204 is simultaneouswith, or synchronous with, or otherwise associated with, the wirelessmessage 206 that contains the first vehicle's identification code. Othervehicles can then detect the localization signal 204 and therebydetermine which vehicle in traffic is associated with that particularidentification code, and thereby determine which particular vehicle isthe first vehicle 201. After localizing each of the other vehicles, anddetermining which of the physical vehicles is associated with which ofthe identification codes, each vehicle can thereafter collaborate andcooperate far more effectively to avoid hazards.

In the diagram, the second vehicle 202 is equipped with a localizationsignal detector 208 such as an infrared camera, and can thereby localizethe first vehicle 201 spatially, and thereby determine that the firstvehicle 201 is the source of the localization signal 204. Additionally,the second vehicle 202 includes a wireless receiver 207, and can therebyassociate the first vehicle's identification code with the direction ofthe first vehicle 201, and thereby identify and localize the firstvehicle 201.

After determining the location of the first vehicle 201 (by imaging thelocalization signal 204) and determining the first vehicle'sidentification code (by receiving a concurrent wireless message 206),the second vehicle 202 can then communicate with the first vehicle 201with knowledge of the first vehicle's location relative to the secondvehicle 202. In addition, the second vehicle 202 can continue to trackthe first vehicle 201 optically, using visible light imagers or infraredcameras for example, thereby determining where the first vehicle 201 ispositioned relative to the second vehicle 202 as long as the firstvehicle 201 remains in view. If the second vehicle 202 loses track ofthe first vehicle 201, the second vehicle 202 can transmit a wirelessmessage to the first vehicle 201 requesting that the first vehicle 201again emit its localization signal. The second vehicle 202 can includethe first vehicle's identification code in the message so as to specifythat the first vehicle 201 is the intended recipient of the message, andcan also include the second vehicle's identification code in the messagewith an indication that this is the transmitting vehicle's code.

It is generally not feasible to direct a wireless message to aparticular vehicle by forming a collimated or directed electromagneticbeam at wireless frequencies. Beam-forming generally requires highfrequencies and/or large rotatable antennas, both of which are expensiveand cumbersome. Instead, a vehicle can send a wireless messagespecifically to another vehicle by broadcasting the messageomnidirectionally, and including the identification code of the intendedrecipient in the message. Other vehicles that pick up the message canthen determine, from the identification code, that the message is notintended for them, and can ignore it.

FIG. 3A shows two vehicles exchanging localization signals, but in thiscase the vehicle identification code is encoded within the localizationsignal itself, rather than being transmitted by a separate wirelessmessage. A first vehicle 301 includes a localization signal emitter 303,which is emitting a localization signal 304 that includes the firstvehicle's identification code embedded or encoded within thelocalization signal 304. For example, the localization signal 304 maycomprise a series of short and long pulses, or pulses with short andlong interpulse intervals, or other modulation configured to convey orindicate the identification code of the first vehicle 301. The encodingmay be in the form of Morse code, or ASCII, or BCD, or straight binary,or one of the many six-bit encodings, or other suitable encodingprotocol that includes the symbols or elements of the emitting vehicle'sidentification code. For example, if the vehicle identification code isits VIN number or its license plate symbols, then the localizationsignal emitter 303 may be modulated so as to encode the symbols of thefirst vehicle's license plate or VIN. The encoded localization signal304 may further include a state or province symbol and/or country codeto further reduce the likelihood of coincidental matches in two vehicleidentification codes. The localization signal 304 may also include aStart-symbol and an End-symbol indicating the start and end of theencoded message, or a formatting or operational symbol, or other symbolsfor various purposes.

The first vehicle 301 may include a localization signal detector 308configured to detect encoded localization signals from other vehicles,thereby reading the identification code contained in the localizationsignal 314. The localization signal detector 308 may be a directionaldetector that indicates the direction of the second vehicle 302, or animaging type detector such as a camera, or it may be a non-directionaldetector that merely reads the localization signal code pulses, while adifferent sensor determines the direction of the localization signal 314without reading the individual pulses. Some directional detectors haveinsufficient time resolution to resolve the individual pulses, whilesome high-speed detectors lack imaging capability, but the combinationof a fast non-directional detector with a slower directional detectormay acquire the pulse-coded information and the directional informationat the same time. The first vehicle 301 determines which of the othervehicles is associated with which identification code according to themodulation pattern of each received localization signal. One advantageof providing two separate sensors—a fast sensor to detect the individualpulses of the localization signal, and a separate imaging detector thatdetermines the spatial location of the emitting vehicle—may be to reducecosts, since an imaging system with fast time resolution may be moreexpensive than the two separate units. Many cameras cannot follow arapidly-varying pulsed signal.

The second vehicle 302 also includes a second localization signalemitter 313 configured to emit coded localization signals 314 in whichthe second vehicle's identification code is embedded. The second vehicle302 may also include an imaging localization signal detector 318. Thus,the second vehicle 302 can determine which vehicle, of several proximatevehicles, is the first vehicle 301 according to the location of thefirst localization pulse 304 on an image produced by the imaginglocalization pulse detector 318. In this way, the second vehicle 302localizes the first vehicle 301 and associates the first vehicle'sidentification code with the first vehicle 301.

Although hailing messages and other wireless messages were not involvedin exchanging the coded localization signals 304-314 in this example,subsequent wireless communication may be exchanged between the twovehicles 301-302 after they are localized and their identification codesexchanged. Thus, the two vehicles 301-302 can cooperate in solvingtraffic problems by exchanging wireless messages that include theirrespective identification codes, without further localization signals,unless they are needed to re-localize their respective positions.

FIG. 3B is a notional schematic showing a series of pulses such asinfrared or visible light pulses comprising a coded localization signal.As an example, the vehicle identification code may be the license platecode of the emitting vehicle, which in this case is “ABC123”. Theexemplary coded localization signal includes a “Start” code, followed bythe codes for the letters and numbers of the license plate, andterminated by an “End” code. In this notional example, the Start code istwo short pulses with a small separation, the End code is a single shortpulse after a long space, and the various letters and numbers areindicated by various long and short pulses with long or short interpulsespaces. The pulses may have any duration, but typically are very brief.For example, the short pulses may be 1 microsecond long and the longpulses may be 2 microseconds long, and likewise the interpulse periodsmay be 1 and 2 microsecond respectively. In that case, a localizationsignal comprising a Start symbol, seven license plate symbols (or othernumber of symbols as per respective state and/or country requirements),and an End symbol, and optionally a state or province indicator, may becompleted in a very short time such as 50-100 microseconds, depending onthe encoding protocol used. In another exemplary system, the shortpulses may be 1 microsecond in duration and the long pulses may be 2microseconds, and the entire localization message may occupy a time ofless than 1 millisecond. In other embodiments, the duration of thelocalization signal may be less than 0.1 second or less than 1 second,depending on encoding details.

No specific coding is implied by the notional graphic depicted. Manydifferent coding protocols are possible. Preferably, all autonomousvehicles should use the same encoding protocol so that they caninterpret other vehicles' coded localization signals, or at least shouldbe configured to correctly decode the encoded localization signals ofthe other vehicles if they use different encoding standards. Anadvantage of embedding the identification code into the opticallocalization signals, rather than in a separate wireless signal, may beto avoid cluttering the radio band with unnecessary wireless messages.If the coded localization signal is garbled or otherwise notdecipherable to another vehicle, then that other vehicle can transmit awireless message requesting that the coded localization signal should berepeated, or alternatively requesting that the code be sent by wirelessmessage instead.

As a further option, the localization signal emitter may be configuredto emit coded signals other than vehicle identification codes. Forexample, after detecting an imminent collision, a vehicle may emit asignal encoding “SOS” or “STOP” or other agreed-upon code to warn othervehicles to keep away.

FIG. 4A is a schematic showing an exemplary sequence of wirelessmessages and localization signals versus time. Depicted is a Mode-1localization procedure in which a non-coded localization signal isemitted synchronously with each wireless message. Accordingly, theschematic shows three wireless messages spaced apart in time, and threelocalization signals emitted concurrently with the wireless messages.Other vehicles can receive the wireless messages and can detect thelocalization signals, and thereby determine which vehicle istransmitting each wireless signal. In Mode-1, no vehicle identificationcodes are required because each message includes a concurrent, orotherwise synchronous, localization signal.

FIG. 4B is a schematic showing another exemplary sequence of wirelessmessages and localization signals versus time. Depicted is a Mode-2localization procedure in which each wireless message includes thevehicle identification code of the transmitting vehicle. A localizationsignal is emitted synchronously with the first wireless message, andsubsequent wireless messages do not have an associated localizationsignal. Instead, a receiving vehicle can determine the location of thetransmitting vehicle with the first message, according to the directionof the associated localization signal, and can record the identificationcode received in the message. Then, upon receiving subsequent messagesthat include the same code, the receiving vehicles can determine therebythat the same transmitting vehicle is involved.

The vehicle identification code may be included in a wireless message atthe beginning, or the end, or within the wireless message along with anindicator that indicates that the code is the transmitting vehicle'sidentification code. The transmitting vehicle can also send wirelessmessages without the code, but in that case the receiving vehicles haveno way to determine which vehicle the messages are coming from (unlessthe transmitting vehicle again emits a localization pulse).

FIG. 4C is a schematic showing another exemplary sequence of wirelessmessages and localization signals versus time. Depicted is a Mode-3localization procedure in which the transmitting vehicle'sidentification code is embedded in a localization signal, for example bymodulating a visible or infrared signal. Other vehicles can detect thelocalization signal, and decode the embedded vehicle identificationcode, and thereby determine the location of the emitting vehicle andalso record the identification code of the emitting vehicle. As shown,there is no wireless message associated with the localization signal.Communicating the vehicle identification code optically, rather than bya wireless message, may prevent overloading of the radiofrequencyspectrum while efficiently broadcasting each vehicle's location andidentification to other vehicles. Subsequently, wireless messages arethen transmitted by the emitting vehicle. The identification code, asrevealed in the initial localization signal, is then included in eachwireless message. No further localization signals may be needed, sinceother vehicles have already determined which vehicle has theidentification code initially emitted. However, if a new set of vehiclesarrives in view, the coded localization signal may again be emitted tolocalize the new arrivals.

FIG. 5 is a perspective sketch of an exemplary localization system 500,which may be mounted on a first vehicle (not shown), and configured toemit and receive localization signals. The localization system 500 mayinclude a localization signal emitter 503 configured to emit alocalization signal 504. For example, the localization signal 504 mayinclude one or more pulses of visible or infrared light, and thelocalization signal emitter 503 may include one or more LEDs or otherlamps. In some embodiments, the localization signal emitter 503 mayextend substantially around 360 degrees and may thereby emit thelocalization signal 504 substantially all around the subject vehicle,thereby being visible to other vehicles regardless of their azimuthalposition relative to the first vehicle. Such an emitter is“omnidirectional” if the emitted signal energy is distributed throughoutall or substantially all horizontal directions. A single central emitter703 may be provided as shown, or alternatively, a plurality of emittersmay be provided, such as two emitters on the ends of a vehicle andconfigured to emit around 180 degrees each, or four emitters on thecorners of the vehicle and configured to emit around 90 degrees, orother combination that, together, covers all or substantially all of a360-degree range.

The localization system 500 may further include a localization signaldetector 508. The detector 508 may be an omnidirectional detector whichis configured to detect localization signals from all or substantiallyall horizontal directions. Alternatively, the detector may comprise aplurality of separate detectors positioned around the vehicle andconfigured to detect localization signals from all, or substantiallyall, directions. In addition, the localization signal detector 508 maybe a high-speed optical pulse detector, configured to detect theindividual pulses of a pulse-coded localization signal from otherautonomous vehicles. The main purpose of the detector 508 may be todetect localization signals with sufficient time resolution to resolveindividual pulses and thereby to read the vehicle identification codewhich is embedded or encoded or modulated in the localization signal. Insome embodiments, the detector 508 may be further configured todetermine the direction of the localization signal. For example, thedirection-sensitive localization signal detector 508 may include a largenumber of photodiodes 514, each configured to detect light in thewavelength of the localization signal, and distributed around thedetector 508 with each photodiode 514 being aimed or focused orcollimated in a different horizontal direction. The detector 508 maythereby detect localization signals substantially all around thehorizontal plane, and also may indicate the direction of the emittingvehicle according to which of the photodiodes 514 registered thedetection. Photodiodes sensitive to visible and/or infrared light withsub-microsecond time resolution are readily available.

The localization system 500 may further include an imaging device 511,which may have lenses 512 pointing in various directions, configured toform images of traffic around the subject vehicle. Thus, the imagingdevice 511 may detect the various vehicles and their locations ordirections, while the directional detector 508 may detect the incominglocalization signal and its direction according to which photodiode 514was activated. Thus, the localization system 500 can determine whichvehicle emitted the localization signal. In addition, by correlating theimage with the code that was observed by the detector 508, the emittingvehicle's identification code can be correlated with the physicalvehicle that was recorded in the image. Concordance of the localizationsignal with one of the imaged vehicles can thereby determine both theidentification code and the spatial location of that emitting vehicle.

To consider a specific example, the localization signal 504, and eachlocalization signal from the other vehicles, may comprise a plurality ofbrief pulses in which the emitting vehicle's identification code isembedded. The localization signal emitter 503 may include a sufficientnumber of infrared LEDs pointing around the subject vehicle to coversubstantially all horizontal directions. The localization signaldetector 508 may include a sufficient number of infrared-sensitivephotodiodes or phototransistors or other suitable detector components514, distributed around the periphery and pointed in various directionsto detect localization signal coming from substantially any directionaround the first vehicle. Each detector component 514 may be configuredto have sufficient time resolution and sensitivity to resolve individualpulses of the incoming coded localization signals. The imager 511 may bea visible-light camera or a near-infrared camera or other suitableimaging device, configured to image vehicles around the first vehicleand determine the spatial locations of those vehicles.

As an alternative, the localization signal emitter 503 may have a singleinfrared source along with a conical reflector or other optical elementsconfigured to distribute the localization signal 504 horizontally aroundthe first vehicle. Other suitable optical arrangements are well known.

FIG. 6 is a perspective sketch of another exemplary localization system600. In this example, the vehicle identification code is again embeddedin the localization signal. However, the localization signal detector isnot directional; instead it is configured to read the incomingidentification codes omnidirectionally. At the same time, an imager suchas a camera is sensitive to the localization signal and also to thevarious vehicles in view. The imager thereby images both thelocalization signal flash and the vehicles in a single image, andthereby identifies the emitting vehicle as the one with the flash uponit.

More specifically, the localization system 600 may include anomnidirectional emitter 603 configured to emit a localization signal 604that includes an identification code therein. In addition, a high-speedomnidirectional detector 608 may be configured to detect other vehicles'localization signals and to read the codes therein, such as measuringthe width and timing of a series of pulses comprising the incominglocalization signals. Thus, the detector 608 may read the code but,since it is omnidirectional, the detector 608 does not determine whichvehicle emitted the code, in this example. Concurrently, an imager 611such as a camera with lenses 612 may be configured to record both thevehicles and the localization signal on the same image. The localizationsignal may appear as a flash superposed on one of the vehicles. Forexample, the imager 611 may be a camera sensitive to both visible andinfrared light. Thus, the imager 611 may determine which particularvehicle emitted the localization signal, while the detector 608 readsthe code. Thus, the emitting vehicle's location and code are determined.Imaging devices typically record a scene in frames by accumulating lightor other energy during a predetermined brief interval. In that case, theincoming localization signal (which may be very brief) may appear inonly a single frame, such as the frame which was acquired when the fastlocalization signal was detected by the detector 608. By seeking thelocation of a single-frame transient feature synchronous with thedetected localization signal, the system 600 can thereby determine whichvehicle emitted the localization signal.

FIG. 7 is a perspective sketch of an exemplary localization systemconfigured to image the traffic and an incoming non-coded localizationsignal with two separate imaging devices. The system 700 includes alocalization signal emitter 703 emitting a localization signal 704 suchas an infrared flash. In this embodiment, the localization signal 704 ispulsed but is not encoded; instead, the vehicle identification signal isprovided separately by a concurrent wireless message.

The system 700 further includes two imaging devices: a localizationsignal imaging device 708 such as an infrared camera, and a vehicleimaging device 711 such as a visible-light camera. The localizationsignal imaging device 708 may be configured with lenses 710 to viewaround the first vehicle to detect and image localization signals fromother vehicles. The vehicle imaging device 711 may be configured withlenses 712 to view around the first vehicle to detect the direction orlocation of other vehicles, and specifically whichever vehicle isemitting the localization signal that the localization signal imagingdevice 708 has detected. By correlating the visible and infrared images,the depicted system 700 may localize the emitting vehicle spatially, andby correlating that vehicle with a vehicle identification code, providedin a concurrent or synchronous wireless message, that vehicleidentification code can be associated with the emitting vehicle. Inaddition, the system 700 may track the vehicle so identified using, forexample, the vehicle imaging device 711, and the system 700 may maintainand update the direction or positional information about the identifiedvehicle as it moves through traffic.

FIG. 8 is a perspective sketch of an even simpler exemplary localizationsystem 800 in which a vehicle's turn signals, or other lamps, may beused as the localization signal emitters. The resulting localizationsignal may be coded or non-coded. The emitting vehicle may also providea concurrent or synchronous wireless message that includes theassociated vehicle identification code. Here, an imaging device 811 suchas a camera is configured with lenses 812 to view around the firstvehicle and thereby to detect or record a localization signal emitted byanother vehicle. In this case, the localization signal comprises asingle brief pulse of all four turn signal lamps, synchronized with awireless message that includes the identification code of the emittingvehicle. The imaging device 811 is configured to image the visible-lightlocalization signal from the turn-signal flash along with the vehiclethat emitted it, thereby localizing that vehicle and associating it withthe received identification code.

The imaging device 811, or an associated processor, may be configured todiscriminate the visible-light localization signal from all other lightflashes. For example, any brief flash that is not synchronous with thewireless message may be rejected as background noise. Secondly, thevisible-light localization signal may be configured to have a specifiedduration such as 100 milliseconds, and a specified range such as +/−10milliseconds, thereby enabling the system 800 to reject other lightpulses that may occur. If some other brief flash happens to occur at thesame time as the visible-light localization signal, then the system 800can detect two simultaneous pulses from different directions. If onlyone of the pulses is coming from a vehicle, as opposed to something inthe environment, the receiving vehicle can reject the false signal anddetermine that the flash that came from a vehicle is the correctlocalization signal. However, if two flashes are imaged at the sametime, and are proximate to two different vehicles, with both pulsesbeing coincident with the wireless message, then the first vehicle maynot be able to determine which vehicle is associated with the wirelessmessage, and therefore can reject the event and send a wireless messagerequesting that the vehicle again emit the localization signal. In thisway, each vehicle can determine the position of each other vehicle inview, and can associate each vehicle's identification code with it. Anadvantage of the system 800 configuration may be economy, since it usesthe already existing lights on each vehicle; hence a separate visible orinfrared emitter is not needed, and a separate infrared imager is notneeded, and a separate high-speed pulse detector is likewise not needed.

FIG. 9 is a notional top-view cross-section sketch of an exemplarydirectional detector 900 for detecting localization signals anddetermining their directions. The depicted system 900 comprises a largenumber of sensor components 914 mounted on a circular frame 908 andaimed at different horizontal directions and configured to detect thewavelength and timing of localization signal pulses. Each sensorcomponent 914 has a limited field of view indicated by dashed lines 915,so that an arriving localization signal is observable in only one of thesensor components 914 (or perhaps divided between two adjacent sensorcomponents 914). The direction of the emitting vehicle is thusdetermined by which of the sensor components detected the localizationsignal, and if two adjacent sensor components 914 detected the samelocalization signal, the direction of the vehicle may be determined byaveraging or other combination of the two detecting sensor components914.

Typically in traffic, vehicles are clustered in the front and reardirections relative to a first vehicle, with few if any vehicles oneither side. Therefore, the directional detector 900 may be configuredwith sensor components 914 being distributed about the periphery in anon-uniform way, specifically with forward-viewing sensor components 922being arranged more densely and/or with narrower field of view than theside-viewing sensor components 923. The frontward direction is indicatedby an arrow 921. In this way, vehicles in front and behind the system900 can be discerned and localized even when densely clustered, as in amultilane highway.

FIG. 10 is a notional circuit schematic of one of the sensor components914 of FIG. 9. A localization signal symbolized as an electromagneticwave 1004 is incident on an optical filter 1024 configured to passwavelengths that include the localization signal 1004. A lens 1025focuses the energy onto a biased photodiode 1026, causing a current flowthat transits through a high-pass or other electronic filter 1027 whichmay be configured to admit frequencies corresponding to the pulses of acoded or non-coded localization signal while blocking other frequenciessuch as noise and backgrounds. Then a gain stage, such as an operationalamplifier 1028, amplifies the rapid signal, and a voltage discriminator1020 or the like can sharpen the shape and timing of the detectedpulses. A processor such as a microcontroller 1030 can then record thepulse or pulses, and can indicate that the localization signal 1004 hasbeen detected. Also, if the localization signal 1004 includes anembedded vehicle code, the microcontroller 1030 may be configured todecode it.

FIG. 11 is a notional sketch of an exemplary image 1100 obtained by animaging device such as a camera, configured to record both alocalization signal and the emitting vehicle in the same image. In theimage 1100, four cars 1102 are seen, each with a localization signalemitter 1103 and a wireless transmitter 1105. One of the cars 1101 isemitting a localization signal 1104 which appears along with theemitting vehicle 1101 in the image 1100. The imaging device thusdetermines which of the vehicles 1101-1102 is emitting the localizationsignal 1104. Also, if a vehicle identification code is provided in aconcurrent wireless message or encoded in the localization signal 1104,then the vehicle identification code can be associated with theparticular vehicle 1101 that emitted the localization signal.

FIG. 12 is a notional sketch of an exemplary image 1200 wherein fourvehicles 1202 are seen. Each vehicle 1202 includes turn signal lamps1203. A particular vehicle 1201 is shown emitting a visible-lightlocalization signal 1204 comprising a brief visible-light flash from itsturn signal lamps 1203. In this way, other vehicles can observe and/orimage the surrounding vehicles, detect the visible-light localizationsignal, and thereby determine which vehicle is emitting a visible-lightlocalization signal 1204. In some embodiments, the visible-lightlocalization signal 1204 may include a vehicle identification codeencoded therein, in which case other vehicles may decode thevisible-light localization signal 1204 and thereby determine whichidentification code is associated with the emitting vehicle 1201. Inother embodiments, the emitting vehicle 1201 may transmit a wirelessmessage synchronously with the visible-light localization signal 1204,wherein the wireless message includes the vehicle identification code,in which case other vehicles may detect the visible-light localizationsignal 1204 and the synchronous wireless message, and thereby determinewhich identification code is associated with the emitting vehicle 1201.

FIG. 13 is a schematic showing how a collision scenario may proceedaccording to prior art, in which the vehicles do not have localizationsystems such as those disclosed herein. Each vehicle may be autonomous,or human-driven, or human-driven but with an automatic emergencyintervention system that operates the vehicle to mitigate an imminentcollision, or human-driven with an automatic assistant such as alane-keeping assistant. However, in each case the vehicles have no wayto identify and localize the other vehicles. Consequently, little or nocooperation can be arranged, even in an emergency. The depicted scenarioinvolves successive views of three cars at three successive times. Thescenario ends in a needless collision.

At time t=0, in a lane of traffic demarked by lines 1300, there areshown three automobile icons representing a leading vehicle 1301, asubject vehicle 1302, and a following vehicle 1303. A block arrow suchas 1305 indicates when each vehicle is moving; and when the vehicle isstopped, there is no arrow. Brake lights 1307 show when each vehicle isbraking.

The traffic lane is repeated at three sequential times indicated as t=0,t=T1, and t=T2. For example, T1 may be 1 second and T2 may be 2 seconds.Dashed arrows such as 1306 show how each vehicle's position shifts ateach time. Thus, the figure shows how each car moves during thescenario.

Initially, at t=0, the leading vehicle 1301 has suddenly stopped. Thesubject vehicle 1302 and the following vehicle 1303 are travellingforward because their drivers or autonomous controllers have not yetrealized that the leading vehicle 1301 has stopped.

At time T1, the driver or controller of the subject vehicle 1302 hasdetected that the leading vehicle 1301 has stopped, and is bringing thesubject vehicle 1302 to a stop as rapidly as possible. Meanwhile, thefollowing vehicle 1303 is still traveling forward, but now the followingdriver or controller sees that the subject vehicle 1302 has stopped andfinally applies the brakes in panic.

At time T2, the subject vehicle 1302 has collided with the leadingvehicle 1301, and the following vehicle 1303 has collided with thesubject vehicle 1302, all because there was insufficient time at freewayspeeds for each vehicle to stop. As will be demonstrated below, thecollisions could have been avoided if the vehicles had been configuredwith suitable means for identifying each other spatially.

FIG. 14 shows a similar scenario, but now the vehicles includelocalization systems according to the present disclosure. Bycooperating, they manage to avoid the collisions.

The leading vehicle 1401, the subject vehicle 1402, and the followingvehicle 1403 are in a travel lane. All three vehicles 1401-1403 may beautonomously operated. All three vehicles 1401-1403 include localizationsystems 1404, 1405, and 1406, respectively. The localization systems1404-1406 may be configured to detect and identify and localize theother vehicles 1401-1403 as soon as they are within range, by methodsdescribed elsewhere herein. In the depicted scenario, all three vehicleshave determined each other's identification and relative positionsbefore t=0.

At t=0, the leading vehicle 1401 has suddenly stopped. The subjectvehicle 1402 determines that a collision is imminent and, using thepreviously-determined identification codes and positions of the othertwo vehicles, transmits wireless messages 1407 and 1408 to the leading1401 and following 1403 vehicles respectively. Message 1407 is a requestto the leading vehicle 1401 to move forward to avoid being hit frombehind, and message 1408 is a request to the following vehicle 1403 toimmediately brake strongly to avoid colliding with the subject vehicle1402.

At t=T1, the leading vehicle 1401 is shown moving forward, the subjectvehicle strongly braking 1402, and the following vehicle 1403 is alsobraking strongly in response to the messages 1407-1408.

At t=T2, all three vehicles 1401-1403 have successfully stopped, veryclose but with no collision. This example of collision avoidance waspossible because the localization systems 1404-1406 established whichvehicle 1401-1403 was in which position. Without knowing which vehicleis in which position, the messages 1407-1408 could not have beendirected at the appropriate recipients, particularly since the twomessages 1407-1408 make opposite requests (accelerating versus brakingin this case). Without the benefit of localization, the vehicles couldhave misinterpreted the messages 1407-1408, in which case the leadingvehicle 1401 could have obeyed the braking message 1408, and thefollowing vehicle 1403 could have obeyed the accelerating message 1407,leading to a double collision. By determining which vehicle was in frontand which was behind the subject vehicle 1402, and by determining thevehicle identification codes of each vehicle 1401-1403, the subjectvehicle 1402 was able to specify that the first message 1407 wasintended for the leading vehicle 1401, and the second message 1408 wasintended for the following vehicle 1403, thereby ensuring that thecorrect action would be taken by each vehicle, and thereby avoiding thecollisions.

FIG. 15 is a flowchart showing an exemplary localization procedure inwhich each vehicle emits a localization signal synchronously with eachwireless message (termed Mode-1 above). Vehicle identification codes arenot included in this example, although the vehicles may have them andexchange them aside from the steps shown here. The actions of vehicle-1are shown on the left and vehicle-2 on the right.

First 1501 vehicle-1 transmits a first wireless message and, at the sametime or otherwise synchronously, emits a first localization signal suchas a visible or infrared pulse. Vehicle-2 then 1502 receives the firstwireless message and the first localization signal, and determines 1503which vehicle, of several proximate vehicles, is the vehicle-1 based ona camera image that shows the first localization signal while the firstwireless message was received. Vehicle-2 then 1504 transmits a secondwireless message synchronously with a second localization signal. Theseare received 1505 by the vehicle-1, which thereby localizes vehicle-2.Thereafter 1506 the vehicles may continue to communicate wirelessly,while continuing to emit localization signals synchronously with eachwireless message, thereby indicating which vehicle is associated witheach wireless message. If the other proximate vehicles transmit wirelessmessages, they may emit synchronous localization signals in the sameway, thereby avoiding any confusion as to which vehicle is transmittingeach message.

FIG. 16 is a flowchart showing an exemplary Mode-2 localizationprocedure in which multiple wireless messages are exchanged inpreparation for the localization signal. The actions of vehicle-1 areshown on the left and vehicle-2 on the right. First 1601, vehicle-1initiates the localization procedure by “hailing” other vehicles, thatis, by transmitting a wireless message that identifies vehicle-1 as anautonomous vehicle and requests a mutual localization procedure with anyvehicles in range. Each vehicle-1 message includes vehicle-1's uniqueidentification code (“code-1” in this example). Then 1602, vehicle-2responds with a wireless message indicating that it too is autonomous,and in the same message providing its identification code-2. Then 1603,vehicle-1 sends another wireless message indicating that it is about toemit a localization signal, thereby indicating the location ofvehicle-1. Then 1604, vehicle-1 emits a non-coded localization signal,such as a single infrared pulse. Since the vehicle identification codewas provided in a wireless message, it is not necessary to embed theidentification code-1 in the localization signal. Also, the localizationsignal is synchronized with a vehicle-1 message, thereby associating thecode-1 with vehicle-1. Then 1605, vehicle-2 detects vehicle-1'slocalization signal using, for example, an imaging device sensitive tothe type of energy in the localization signal, such as aninfrared-sensitive camera in this example, thereby localizing vehicle-1and associating it with code-1.

Then 1606, vehicle-2 transmits a wireless message indicating thatvehicle-2's localization signal is forthcoming, along with vehicle-2'sidentification code-2. Vehicle-2 then 1607 emits a localization signalsuch as another infrared pulse. Then at 1608, vehicle-1 detectsvehicle-2's localization signal using an infrared camera for example,thereby localizing vehicle-2 spatially and associating vehicle-2 withidentification code-2. Thereafter 1609, vehicle-1 and vehicle-2 cantrack each other optically using, for example, image analysis, or byradar, or other suitable means for following the positions of vehicles.The vehicles can thereby cooperate with each other using the knowledgeof where each of the vehicles is located. With such cooperation,collisions can be avoided and/or minimized, and traffic can befacilitated generally.

If vehicle-1 moves outside of vehicle-2's field of view, for example dueto a truck passing between them, then vehicle-2 can initiate anotherlocalization procedure to re-localize vehicle-1, or vice-versa. Eithervehicle can transmit localization hailing messages at any time, such aswhen additional vehicles come into range or appear visually, therebylocalizing each vehicle within range.

FIG. 17 is a flowchart showing a simpler exemplary localizationprocedure, in which the vehicle identification is provided in a singlewireless message instead of back-and-forth handshaking. First 1701,vehicle-1 transmits a wireless hailing message that includes itsidentification code-1, and simultaneously emits a non-coded localizationsignal such as a single infrared pulse. Then 1702, vehicle-2 receivesthe wireless message and images the localization signal using, forexample, an infrared camera. Vehicle-2 records the code-1 and theposition of vehicle-1, thereby localizing vehicle-1. Then 1703,vehicle-2 transmits a wireless message with its code-2 andsimultaneously emits a non-coded localization signal such as an infraredpulse. Then 1704, vehicle-1 receives the wireless message and thelocalization pulse from vehicle-2, thereby localizing it. Thereafter1705, the two vehicles can collaborate with knowledge of their relativepositions.

FIG. 18 is a flowchart showing another exemplary localization procedure,in which the identification code is embedded in the localization signalrather than a wireless message (Mode-3). First 1801, vehicle-1 detectsthat an unidentified vehicle-2 has entered its proximity. Then 1802,vehicle-1 emits a coded localization signal, such as a series ofinfrared pulses with its identification code-1 embedded therein. Then1803, vehicle-2 detects the localization signal, and images vehicle-1along with the localization signal, thereby determining the location ofvehicle-1 as well as its identification code-1. Then 1804, vehicle-2emits a coded localization signal that includes its identificationcode-2, and 1805 vehicle-1 receives that signal while imaging vehicle-2,thereby localizing vehicle-2 in association with its identificationcode-2. Thereafter 1806, the vehicles can communicate wirelessly usingthe known identification code-1 and code-2, while continuously trackingthe other vehicle by optical imaging, or radar, or other suitabletracking means. And 1807, either vehicle can request anotherlocalization signal wirelessly if the tracking is interrupted. Anadvantage of this version may be that it avoids cluttering the radiobandwidth with unnecessary wireless messages, since no wireless messagesare involved until one of the vehicles has a need for communication.Another advantage may be that the range is self-limiting, in that anypair of vehicles that cannot see the other vehicle's localization signalwould be considered out of range.

The localization procedure may be configured to avoid signal contentionor overlap, a situation in which two vehicles attempt to transmitwireless messages or localization signals at the same time. For example,signal contention can occur if vehicle-1 transmits a hailing message andtwo other vehicles respond at the same time. To avoid such interference,each vehicle may be configured to wait for a random or pseudorandomwaiting interval after receiving the hailing message, and then torespond if no other vehicle has responded sooner. (Random andpseudo-random are treated as equivalent herein.) In that way, overlap islargely prevented. If a vehicle is prepared to respond to the hailingmessage, but is forced to withhold its response due to interference,then the withholding vehicle may wait until the in-progress localizationprocedure has concluded, and may then respond. In addition, to avoidcreating a second contention situation, the withholding vehicle mayprovide a second waiting period. For example, after detecting that thein-progress localization procedure has concluded, the withholdingvehicle may then wait an additional random interval, and then mayinitiate its response if a third vehicle has not already done so. Thus,the randomized waiting intervals can avoid cascaded contention andinterference.

The random or pseudorandom waiting intervals may be arranged accordingto a random-number algorithm executed by a processor, such as acalculation that selects a number of milliseconds of waiting time, orotherwise. The algorithm that provides the random interval may beconfigured to populate the random intervals uniformly within apredetermined range of waiting times, such as between 1 second and 2seconds. Such a predetermined interval, during which an event can betriggered, is sometimes called a “gate”.

The vehicles may be configured to adjust their random waiting intervalsaccording to various conditions. For example, if a vehicle has beenforced to withhold its response to a hailing message, that vehicle maythen shorten its random waiting interval on the next try, therebyincreasing the likelihood that it can beat the other vehicles. Eachvehicle may be configured to initially start with a rather long waitinginterval such as between 500 and 1000 milliseconds, on the firstattempt. Then, if the vehicle is prevented from responding due to othermessages starting first, the withholding vehicle may shorten the nextrandom waiting interval to between 250 and 500 milliseconds. After eachsuccessive inhibition, the vehicle may halve its range of random waitingintervals, and continue likewise until the withholding vehicle isfinally able to initiate communication without interference. In thisway, each vehicle is likely to have a turn, and the vehicles that havewaited longest automatically become the first in line for the nextattempt. After finally completing a full localization procedure, eachvehicle may restore its random waiting range back to the initial longsetting, so that other waiting vehicles can then have their turn.

The vehicles may be configured to complete the full localizationprocedure in a short time, such as 0.1 or 1 or 10 or 100 millisecondsusing, for example, fast electronic and optical components. In mosttraffic situations, even if dozens or hundreds of other vehicles are inrange, most or all of the vehicles within range may then be able tocomplete their localization procedures in 1 second or a few seconds,typically. In addition, if each vehicle is configured to embed itsidentification code in the localization signal rather than in wirelessmessages, the period of contention may be extremely short, such as only50-100 microseconds in some embodiments, by emitting a correspondinglybrief localization signal.

FIG. 19 is a schematic chart showing the timing of various actionspertaining to a first vehicle's response to another vehicle's hailingmessage. The horizontal axis is time, and each line or item representsan action or a demarked time interval. In the first line, the firstvehicle transmits a hailing message during a time indicated by the pulsemarked HAIL. The line marked GATER represents an electronic clock in thefirst vehicle that is configured to wait, after the end of the hailingmessage, for a predetermined time interval WAIT, and then to open a gateinterval GATE during which the first vehicle can respond to the hailingmessage if no interference is present. A third vehicle is present asindicated by the line THIRD; however, the third vehicle remains silentin this case; hence the line marked THIRD is flat. The first vehiclethen responds to the hailing message at a random (or pseudo-random orotherwise computed) moment within GATE. In summary, the first vehicleavoids interference with other vehicles by waiting for the predeterminedWAIT interval, thereby giving other vehicles a chance to respond. Inaddition, the first vehicle may wait a second random interval after theGATE has opened, to avoid pile-up that could occur if multiple vehiclesall initiated messages at the end of the predetermined WAIT interval.The second interval is marked WAIT-2.

FIG. 20 is a similar schematic, but this time the third vehicle beginstransmitting before the subject vehicle does, and therefore the subjectvehicle had to abort its response and wait until the intruding vehiclehad finished. The HAIL message is shown in the first line. The firstvehicle's timing is shown in the second line GATER, starting with thepredetermined WAIT interval and then opening a gate. However, in thisexample, the third vehicle begins transmitting a message while the firstvehicle's gate is open but before the first vehicle has startedtransmitting. Therefore, the first vehicle, detecting the interference,immediately closed its gate interval, which is labeled as TRUNCATED GATEfor that reason.

After the interfering message has completed, the subject vehicle thenprepares another predetermined delay labeled SECOND WAIT. Since thefirst vehicle was forced to withhold its message, the SECOND WAITinterval is shorter than the original WAIT interval. The first vehiclethen opens another gate interval labeled SECOND GATE, during which aresponse may be transmitted at some random moment. The last line shows,in dash, the originally planned response message labeled ABORTEDRESPONSE, which was aborted due to the interference. The final message,labeled RESPONSE, was then transmitted within the SECOND GATE. TheSECOND WAIT interval is configured to be shorter than the original WAITinterval so that the first vehicle would have an increased likelihood ofbeing able to start its RESPONSE before another vehicle beginstransmitting. The first vehicle initially started with a relatively longWAIT interval so that other vehicles could have a chance, particularlythose other vehicles that were previously forced to withhold theirresponses. The first vehicle then prepares successively shorter waitintervals after each aborted response, to increase the likelihood thatit will be able to transmit. The intent of the successively shorter waitintervals is to give the first vehicle an advantage relative to othervehicles that have not had to withhold their messages, but not to gainadvantage relative to the vehicles that have already withheld theirmessages longer than the first vehicle. If all the vehicles adopt thesame standards for the waiting and gating intervals, the method providesthat each vehicle will get a turn, with those waiting the longestgetting successively higher priority in timing.

In some embodiments, the initial hailing message may contain informationthat would allow other vehicles to filter their response. It may notmake sense to try to localize certain other vehicles, or even to attemptcommunication with them. For example, the hailing message may includethe hailing vehicle's identification code, so that other vehicles thathave already localized that hailing vehicle can ignore the message. Forexample, “Hail, other vehicles! I'm ABC123. Please respond if you havenot already done so.” Other vehicles that have already localized ABC123could then ignore the message.

In other embodiments, the hailing message may indicate the direction oftravel of the transmitting vehicle, such as “Hail, other vehicles! I'mtraveling north. Please respond if you are too.” Other vehicles that aretraveling in the opposite direction may ignore the message, since thetwo vehicles will likely be out of range soon and there is no reason toattempt to localize each other.

In a similar way, the hailing message may contain information about theroad being traveled, such as “I'm traveling north on route 15 in lane1.” Then another vehicle which is proximate but is on another road, suchas an access road, may ignore the message as not relevant. Likewise,another vehicle that is traveling in the same direction on the sameroad, but widely separated from the hailing vehicle may elect to ignorethe message, for example a hailing vehicle in lane 4 and a respondingvehicle in lane 1 may be so far apart that localizing would bepointless. Vehicles in HOV lanes may decline to communicate withvehicles in non-HOV lanes, or vice-versa, since these lanes are supposedto be separate (other than crossover sections). On the other hand, theremay be circumstances in which vehicles on crossing roads would benefitfrom mutual localization, such as when two surface streets intersect ata stop sign or a traffic light for example. A vehicle approaching theintersection may hail a vehicle on the cross street to ensure that thecrossing vehicle is out of the way before the first vehicle expects toarrive at the intersection, and many similar situations. Thus, thevehicles may be configured to adjust their criteria for responding tohailing messages according to the type of road, with differentthresholds and conditions applicable to freeway driving versus surfacestreets, and dense city traffic versus rural roads, for example.

In addition, the vehicles may adjust their criteria for accepting orignoring other vehicles' hailing messages according to the trafficdensity. For example, if the number of other vehicles in range is large,such as over 10 or 20 or 50 other vehicles, then the vehicles maydiscard the messages of other vehicles that are farthest away, or ofthose vehicles that are judged to be less of a hazard.

FIG. 21 is a flowchart showing an exemplary method for mitigating animminent collision. The method includes cooperation between the firstvehicle and a second vehicle if possible. If cooperation is notpossible, the first vehicle takes action independently. In either case,the first vehicle prepares a plurality of sequences of actions, eachaction being a steering and/or braking and/or positively acceleratingaction, and then determines which sequence will avoid the collision. Ifnone of the sequences will avoid the collision, then the first vehiclecalculates the amount of harm caused by each projected collisionaccording to the various sequences, and then implements the sequencethat results in the least harm.

First 2101, the first vehicle detects the second vehicle using, forexample, sensors. In this example, the second vehicle is not yet ahazard, and there is plenty of time for the vehicles to exchangeinformation. The first vehicle then 2102 attempts to engage the secondvehicle by emitting a coded localization signal, with the firstvehicle's identification code embedded in the signal. If 2104 the firstvehicle receives no acknowledgement, it then performs 2105 an unassistedcollision mitigation by selecting the best sequence of actionsavailable. If, on the other hand, the first vehicle does receive anacknowledgement from the second vehicle at 2104, such as a codedlocalization signal, then the two vehicles are able to cooperate and toseek a better outcome. The first vehicle then 2106 records the secondvehicle's identification code and notes the position of the secondvehicle using, for example, an imaging device that detects both thelocalization signal and the second vehicle, such as a camera configuredto detect both visible and infrared light.

The first vehicle then 2107 calculates future positions of the first andsecond vehicle and 2108 determines if the vehicles are projected tocollide. If not, the system resumes scanning the traffic for otherhazards. If the vehicles are projected to collide, the two vehiclesbegin to wirelessly communicate 2109 to develop mitigation strategies.For example, both vehicles' processors can devise and analyze sequencesof actions designed to avoid the collision, and to determine 2110whether the collision can be avoided by any of those sequences. If so,then 2111 one of the strategies that avoids the collision is selectedand mutually communicated 2112. The vehicles then 2113 mutuallyimplement the avoidance strategy by carrying out their respectivesequences of actions. For example, one of the vehicles may beginaccelerating while the other vehicle decelerates so as to avoid thecollision. If, on the other hand, the collision is unavoidable by any ofthe strategies, then 2114 the two vehicles mutually calculate the harmexpected according to each of the sequences of actions, and select theparticular strategy that is projected to cause the least harm in thesubsequent collision. The two vehicles can then 2115 communicate tosynchronize their actions, and 2116 implement the least-harm strategy.In addition, the vehicles can continue to communicate and assist eachother after an unavoidable collision.

FIG. 22 is a flowchart showing a similar localization procedure, but nowan imminent collision is detected first, and then a rapid localizationprocedure is carried out to enable cooperation. First 2201 the firstvehicle detects a second vehicle and 2202 calculates future positions ofthe two vehicles and determines 2203 whether they are projected tocollide. If not, the flow returns to the beginning to continue watchingthe second vehicle and any other vehicles in view. But if a collision isprojected, then the first vehicle may initiate two parallel tasks, tocalculate 2204 a sequence of actions to mitigate the collision withoutcooperation, and 2205 to transmit a hailing message seeking urgentcommunication with the second vehicle. If the second vehicleacknowledges the hailing message 2206, then the two vehicles quicklyperform the localization procedure 2207 as described hereinabove, andcalculate various actions they may cooperatively take 2208 to avoid orminimize the collision. If, however, no acknowledgement is received atstep 2206, the first vehicle continues to calculate solo unassistedcollision-avoidance and collision-minimization actions 2204. In eithercase, the first vehicle then 2209 determines whether the collision isavoidable if any of the collision-mitigations actions have beenprojected to avoid the collision, and unavoidable otherwise. If thecollision is unavoidable, then the first vehicle (possibly incollaboration with the second vehicle or other vehicles at risk) mayselect 2210 a particular sequence of actions to minimize the harm of theunavoidable collision, and then may implement 2212 the selectedsequence. If, however, at least one of the sequences of actions isprojected to avoid the collision, then 2211 the first vehicle (possiblyin collaboration) selects one of the collision-avoidance sequences and2213 implements it. Then, flow returns to the beginning 2201 to resumewatching for other threats.

When the first vehicle has succeeded in localizing and identifying theother vehicles around it, the first vehicle and the other communicatingvehicles can collaboratively devise the collision-mitigation sequenceand can implement the sequence cooperatively. The sequence of actionsmay include some actions to be carried out by the first vehicle andother actions to be carried out by the second vehicle; for example, onevehicle braking while the other vehicle accelerates. Likewise, thesequence of actions may include actions for three vehicles, which mayinclude vehicles not directly involved in the projected collision. Forexample, a vehicle in a lane adjacent to the first vehicle may berequested to brake or swerve so that the first vehicle can dash into theadjacent lane and avoid hitting the leading vehicle. The cooperativesequence of actions may include timing parameters, such as two vehiclesbraking at the same time, or one vehicle braking only after anothervehicle has pulled one car length ahead, for example.

If, on the other hand, a collision is imminent and the other vehiclecannot establish communication or localization with the first vehicle,then the first vehicle may proceed to select and implement the best“solo” or unassisted sequence of actions to mitigate the collision,since there are no other options available. In general, a collaborativemitigation in which both vehicles take coordinated action to avoid acollision is likely to be more successful than a solo or unassistedmitigation effort. For that reason, the localization and identificationsystems and methods disclosed herein are expected to reduce trafficcollisions, and to minimize any unavoidable collisions that occur, andto save lives.

The system and method may be fully implemented in any number ofcomputing devices. Typically, instructions are laid out on computerreadable media, generally non-transitory, and these instructions aresufficient to allow a processor in the computing device to implement themethod of the invention. The computer readable medium may be a harddrive or solid state storage having instructions that, when run, orsooner, are loaded into random access memory. Inputs to the application,e.g., from the plurality of users or from any one user, may be by anynumber of appropriate computer input devices. For example, users mayemploy vehicular controls, as well as a keyboard, mouse, touchscreen,joystick, trackpad, other pointing device, or any other such computerinput device to input data relevant to the calculations. Data may alsobe input by way of one or more sensors on the vehicle, an insertedmemory chip, hard drive, flash drives, flash memory, optical media,magnetic media, or any other type of file—storing medium. The outputsmay be delivered to a user by way of signals transmitted to vehiclesteering and throttle controls, a video graphics card or integratedgraphics chipset coupled to a display that maybe seen by a user. Giventhis teaching, any number of other tangible outputs will also beunderstood to be contemplated by the invention. For example, outputs maybe stored on a memory chip, hard drive, flash drives, flash memory,optical media, magnetic media, or any other type of output. It shouldalso be noted that the invention may be implemented on any number ofdifferent types of computing devices, e.g., embedded systems andprocessors, personal computers, laptop computers, notebook computers,net book computers, handheld computers, personal digital assistants,mobile phones, smart phones, tablet computers, and also on devicesspecifically designed for these purpose. In one implementation, a userof a smart phone or WiFi-connected device downloads a copy of theapplication to their device from a server using a wireless Internetconnection. An appropriate authentication procedure and securetransaction process may provide for payment to be made to the seller.The application may download over the mobile connection, or over theWiFi or other wireless network connection. The application may then berun by the user. Such a networked system may provide a suitablecomputing environment for an implementation in which a plurality ofusers provide separate inputs to the system and method. In the belowsystem where vehicle controls are contemplated, the plural inputs mayallow plural users to input relevant data at the same time.

It is to be understood that the foregoing description is not adefinition of the invention but is a description of one or morepreferred exemplary embodiments of the invention. The invention is notlimited to the particular embodiments(s) disclosed herein, but rather isdefined solely by the claims below. Furthermore, the statementscontained in the foregoing description relate to particular embodimentsand are not to be construed as limitations on the scope of the inventionor on the definition of terms used in the claims, except where a term orphrase is expressly defined above. Various other embodiments and variouschanges and modifications to the disclosed embodiment(s) will becomeapparent to those skilled in the art. For example, the specificcombination and order of steps is just one possibility, as the presentmethod may include a combination of steps that has fewer, greater, ordifferent steps than that shown here. All such other embodiments,changes, and modifications are intended to come within the scope of theappended claims.

As used in this specification and claims, the terms “for example”,“e.g.”, “for instance”, “such as”, and “like” and the terms“comprising”, “having”, “including”, and their other verb forms, whenused in conjunction with a listing of one or more components or otheritems, are each to be construed as open-ended, meaning that the listingis not to be considered as excluding other additional components oritems. Other terms are to be construed using their broadest reasonablemeaning unless they are used in a context that requires a differentinterpretation.

What is claimed is:
 1. A system, mounted on a first vehicle, forlocalizing a second vehicle, comprising: a wireless transmitterconfigured to transmit a first wireless message; a localization signalemitter configured to emit a first localization signal comprising pulsedenergy synchronized with the first wireless message; a wireless receiverconfigured to receive a second wireless message from the second vehicle;a localization signal detector configured to detect a secondlocalization signal from the second vehicle, the second localizationsignal comprising pulsed energy synchronized with the second wirelessmessage; and a processor configured to cause the localization signalemitter to emit the first localization signal synchronously with thefirst wireless message, to determine a direction of the second vehicleaccording to the second localization signal, and to associate the secondlocalization signal with the second wireless message; wherein theprocessor is further configured to perform one or more of the followingsteps: determine which particular vehicle, among a plurality of othervehicles, is the second vehicle according to the direction determinedfrom the second localization signal; decode the second identificationcode by analyzing the second localization signal; identify the secondvehicle by comparing an image of the second vehicle and the directiontoward the second vehicle; form a plurality of successive images of thesecond vehicle at successive times, and to calculate an updateddirection toward the second vehicle according to each of the pluralityof images; communicate with the second vehicle after determining both adirection toward the second vehicle and an identification codeassociated with the second vehicle; avoid, in cooperation with thesecond vehicle, an imminent collision; cause the second vehicle to avoidan imminent collision, at least in part by communicating with the secondvehicle; determine, based at least in part on one or more communicationswith the second vehicle, whether an imminent collision is avoidable orunavoidable; mitigate a traffic collision by communicating wirelesslywith the second vehicle after detecting the second localization signaland determining which vehicle, among a plurality of vehicles proximateto the first vehicle, is the second vehicle; determine the secondidentification code, and then to transmit, specifically to the secondvehicle, a wireless message that includes both the first and secondidentification codes; determine whether the second vehicle is anautonomous vehicle; prepare, in cooperation with the second vehicle, afirst sequence of actions comprising a plurality of sequential positiveaccelerations, active or passive decelerations, waiting times, orsteering actions of the first vehicle, and a second sequence of actionscomprising a plurality of sequential positive accelerations, active orpassive decelerations, waiting times, or steering actions of the secondvehicle; avoid a collision, at least in part by communicating with thesecond vehicle after determining a direction toward the second vehicleand an identification code associated with the second vehicle;communicate with the second vehicle, and to prepare, at least in partbased on communications with the second vehicle, one or more sequencesof actions configured to avoid the collision or to minimize the harm ofan unavoidable collision, and to implement a selected one of thesequences of actions; determine, at least in part based oncommunications with the second vehicle, whether an imminent collision isavoidable or unavoidable; wait, after receiving a wireless message fromthe second vehicle, for a predetermined waiting interval, and then toprepare a gate interval, and to emit the first localization signal at arandomly selected time during the gate interval; and delay emitting thefirst localization message while another wireless message is inprogress.
 2. The system of claim 1, wherein the processor is configuredto wait, after receiving a wireless message from the second vehicle anddetermining that another wireless message has been transmitted duringthe predetermined waiting interval, for a second waiting interval, andthen to prepare a second gate interval, and to emit the firstlocalization signal during the second gate interval.
 3. The system ofclaim 2, wherein the second waiting interval is shorter than thepredetermined waiting interval.